The sunflower seed is the fruit of the sunflower (Helianthus annuus). The term "sunflower seed" is actually a misnomer when applied to the seed in its pericarp (hull). Botanically speaking, it is a cypsela. When dehulled, the edible remainder is called the sunflower kernel or heart.

There are three types of commonly used sunflower seeds: linoleic (most common), high oleic, and NuSun. Each variety has its own unique levels of monounsaturated, saturated, and polyunsaturated fats. The information in this article refers mainly to the linoleic variety.

Sunflower seeds are more commonly eaten as a healthy snack than as part of a meal. They can also be used as garnishes or ingredients in various recipes. The seeds may be sold as in-shell seeds or dehulled kernels. The seeds can also be sprouted and eaten in salads.

When in-shell seeds are processed, they are first dried. Afterwards, they may also be roasted or dusted with salt or flour for preservation of flavor. Dehulling is commonly performed by cracking the hull with one's teeth and spitting it out while keeping the kernel in the mouth and eating it.

Sunflower seeds sold by the bag are either eaten "plain" (salted only) or with a variety of flavorings added by the maker including barbecue, pickle, hot sauce, bacon, ranch, and nacho cheese as well as others.